new guy with 07.5 silverado problems

Hello everyone just picked up my first silverado 07 nnbs ext cab 5.3 z71 ltz 57k miles..bought it as a refundable wreck because its mainly what I buy..this may be lengthy but I have some issues. First off I've had the truck back two days now there is a huge exhaust leak , and the truck has no power like its in limp mode. The 4wd will not engage , when you turn the know it goes to 4hi the light stays solid, the switch the know to 4lo in neutral it just blinks..further more there is no indicator light under the p,r,n,d,3 and so on. Speedo Is dead but tach works and no fuel mpg readings ..the tire pressure monitor is working tells you when the door is opened and so on . The stereo,lights,signals,heated seats all work. It does have a check engine light but haven't pulled code yet. All wires seem to be ok..it appears to be missing some fuses but with no owners manual or fuse box lid its hard to see what they are..I got a great deal on the truck so its ok if I spend some money. Thanks in advance for any advice !

Your 07" Silverado NNBS with the LTZ Trim is a GMT-900 Series which is going to be the 2007" and up Silverado's/Sierra's .......the Problems with the Stepper Motor's are a Common problem as Amy mentioned above.......on the GMT-800 Series.....99" to 07" Trucks/SUV's.

*update* put a new tcm on and got it flashed..still no worky..Went through the fuse box for a second time.......TCM BATT fuse blow :great:everything works now as it should. Now to all the other odds and ins. Thanks guys for any input involved!